1. Field of the Invention
The present invention relates to a magnetic recording and reproducing apparatus and, more particularly, to a magnetic recording and reproducing apparatus arranged to perform magnetic recording and reproduction on or from a tape-shaped recording medium by pulling our the tape-shaped recording medium from a cassette and wrapping the tape-shaped recording medium around a drum.
2. Description of Related Art
FIG. 18 is a plan view showing, by way of example, the arrangement of a conventional magnetic recording and reproducing apparatus. A magnetic tape 101 serving as a recording medium is supplied from a supply reel 102 through a tension pole 103, tape guides 104, 105 and 106 to be wrapped around a rotary cylinder (drum) 107 which has recording and reproducing heads mounted thereon. After that, the magnetic tape 101 is taken up by a take-up reel 113 through tape guides 108 and 109, a tape driving capstan 110, a pinch roller 111 and another tape guide 112.
Referring next to FIG. 19 and FIGS. 20(a) and 20(b), a reel mount driving mechanism provided in the magnetic recording and reproducing apparatus is described below.
FIG. 19 is a side view of a supply reel mount driving mechanism which is shown in FIG. 18. The supply reel 102 (the take-up reel 113) is fitted on a reel shaft 115 (116), which is mounted on a slide chassis 114, to be rotatable around the reel shaft 115 (116). FIGS. 20(a) and 20(b) show, in an enlarged side view and a top view, respectively, the arrangement of the supply reel mount driving mechanism. The take-up reel mount driving mechanism is also arranged in exactly the same manner as the supply reel mount driving mechanism shown in FIGS. 20(a) and 20(b).
Referring to FIG. 18, the driving force of a capstan motor 150 which is disposed on a main chassis 117 is transmitted by means of gears 118 to 121, a belt (not shown), etc., to a gear 123 which is rotatably fitted on a shaft 122 mounted on the main chassis 117. The driving force transmitted to the gear 123 is transmitted further to a gear 126 which is rotatable around a shaft 125 mounted on a lever 124, which is arranged to be swingable around the shaft 122. The gear 126 and the lever 124 are arranged to engage each other through a torque transmitting means (not shown). The lever 124 is arranged to be caused by the rotation of the gear 123 to swing around the shaft 122. When the gear 123 rotates counterclockwise, the gear 126 meshes with a gear 127.
Referring to FIGS. 20(a) and 20(b), the details of the supply reel mount driving mechanism of the conventional arrangement are described below. The gear 127 is provided with a hysteresis plate 128 which is insert-molded. A gear 129 is provided with a yoke plate 130 which is insert-molded. A magnet 131 is magnetically attracted by the yoke plate 130. A reel claw 133 and a reel claw spring 134 are mounted on the gear 129. A reel cap 132 is press-fitted in the gear 129. The reel claw 133 is under an upward urging force of the reel claw spring 134. However, the position of the reel claw 133 is restricted by the reel cap 132.
The gears 127 and 129 are caused by the magnet 131 which is magnetically attracted by the gear 129 to be magnetically attracted and pulled to each other at a contact part 136 of the gear 127 and a contact part 137 of the gear 129 across a washer 135.
The supply reel 102 is rotatably fitted on the reel shaft 115 which is mounted on the slide chassis 114.
Here, when the gear 126 moves in the direction of an arrow xe2x80x9caxe2x80x9d shown in FIG. 20(a) to mesh with the gear 127, a hysteresis loss brought about by the magnet 131 and the hysteresis plate 128 and a friction loss brought about by the contact part 136 of the gear 127, the contact part 137 of the gear 129 and the washer 135 cause a driving force to be transmitted from the gear 127 to the gear 129 with a certain fixed amount of torque.
Referring to FIG. 18, when the gear 123 rotates counterclockwise, the lever 124 swings counterclockwise around the shaft 122. Then, following the counterclockwise movement of the lever 124, the gear 126 moves, while rotating, up to such a position as to mesh with the gear 127. As a result, the gear 127 (and the supply real 102) rotates counterclockwise, i.e., in the direction of rewinding the tape 101 in this instance. Then, the tape 101, which is wound around a reel hub 138 shown in FIG. 20(a), is taken up and wound around the supply reel 102 by means of the reel claw 133.
In this instance, the magnetic tape 101 is taken up and wound with a certain fixed amount of torque produced by the above-stated torque transmission means (the hysteresis loss caused by the hysteresis plate 128 and the magnet 131 and the friction loss caused by the contacts parts 136 and 137 and the washer 135 as mentioned above).
Referring further to FIG. 18, a T(take-up)-reel-side soft brake 140 and a T-reel-side lock brake 141 are fitted on a shaft 139 mounted on the slide chassis 114, and a S(supply)-reel-side lock brake 143 is fitted on a shaft 142 mounted on the slide chassis 114. A loading motor 144 is arranged to operate, through a leading gear train (not shown), a mode lever (not shown), etc., to turn on and off the T-reel-side soft brake 140, the T-reel-side lock brake 141, the S-reel-side lock brake 143, etc., according to the operation mode of the magnetic recording and reproducing apparatus. The T-reel-side soft brake 140, the T-reel-side lock brake 141 and the S-reel-side lock brake 143 are arranged to apply soft and lock brakes by coming into contact or meshing with the gear 127 and the gear 129 shown in FIG. 20(a).
In the case of the conventional arrangement shown in FIG. 18, the reel mounts are disposed on the slide chassis 114. A torque limiter (clutch) mechanism is arranged inside each of the reel mounts. In addition to that, brake contact parts are also arranged at the reel mounts. Therefore, each of the reel mounts thus has a complex structural arrangement, which necessitates having a large thickness between the lower part of the cassette and the slide chassis 114, and which thus causes an increase in cost.
Further, in general, in the conventional magnetic recording and reproducing apparatuses, for example, a recorder deck of a camera-integrated-type video tape recorder (VTR) is arranged to have its mechanism installed on the upper surface of a chassis thereof because of the restrictions imposed by the shape and size of a cassette, the size of the apparatus itself, etc., and a stationary-type video tape recorder (VTR) is arranged, conversely, to have its mechanism installed on the back side of a chassis thereof.
However, the conventional magnetic recording and reproducing apparatuses, such as a recorder deck of a camera-integrated-type VTR, have presented such a problem that it is necessary to arrange a large clearance between a tape transport member and a tape loading driving member for the purpose of preventing lubricative grease or the like in a driving part of the tape transport member from sticking to a tape transport part of the tape transport member to soil the tape, or for the purpose of preventing the tape transport member and the tape loading driving member from interfering with each other. The necessity of having such a large clearance hinders a reduction in size of the apparatus.
On the other hand, in the case of a stationary-type VTR, a tape loading driving part is arranged on the back surface of a chassis, while guide posts provided for guiding the travel of a tape are arranged on the upper surface of the chassis. Although such an arrangement effectively prevents the guide posts from being soiled by grease or the like, since the surface of the chassis is arranged to have guide grooves for a pulling-out action of the guide posts on the tape, it is impossible for such an arrangement to cope with a tape path arranged to perform a three-dimensional loading operation (i.e., when pulling out the tape, the guide posts move upward with respect to the surface of the chassis) designed for aiming at reducing the size of the apparatus as adopted in the tape transport system of video cameras.
Further, in a mechanical deck of the conventional video tape recorder (VTR), a capstan is mounted on a chassis, and sensors of various kinds are packaged on a flexible printed circuit board stuck to the chassis.
In the case of the conventional arrangement described above, however, it is necessary to have a certain space for mounting the capstan on the chassis. Such a mounting space hinders a reduction in size of the apparatus.
Further, the flexible printed circuit board is expensive. Besides, since there is provided wiring for the sensors separately from wiring for the capstan, it is necessary to have many connectors arranged for the wiring for the sensors and the wiring for the capstan. The use of many connectors causes an increase in cost of the apparatus.
Such being the background, the invention is directed to the solution of the problems of the prior art described above. It is, therefore, an object of the invention to provide a reel mount driving mechanism which is arranged for a magnetic recording and reproducing apparatus to permit a reduction in number of parts of the apparatus, to be simple in structure of the apparatus, to permit a reduction in thickness of the apparatus and thus to permit a reduction in cost of the apparatus.
It is another object of the invention to provide a magnetic recording and reproducing apparatus arranged to prevent grease in a tape loading driving mechanism from sticking to guide posts, to enable guide members to perform the above-mentioned three-dimensional loading operation, and to enhance the reliability of traveling of a tape and a reduction in size of the apparatus.
It is a further object of the invention to provide a magnetic recording and reproducing apparatus arranged to permit a reduction in size and cost thereof.
To attain the above objects, in accordance with an aspect of the invention, there is provided a magnetic recording and reproducing apparatus, which comprises guide posts arranged to pull out a tape-shaped recording medium from a cassette and wrap the tape-shaped recording medium around a drum, guide members arranged to support the guide posts, arms arranged to move the guide members, and arm driving parts arranged to cause the arms to swing, wherein the arms and the arm driving parts are disposed respectively on different sides of a chassis.